Perthes disease, also known as Legg-Calvé-Perthes disease, is a childhood condition causing the temporary loss of blood supply to the femoral head. This leads to bone death and deformity of the hip joint. It most commonly affects boys between the ages 4-8 years old. The exact cause is unknown but may involve genetic and vascular factors. Symptoms include a limp or hip pain. Diagnosis is made through x-rays showing changes to the femoral head such as fragmentation. Prognosis depends on factors like age of onset and extent of femoral head involvement. Treatment aims to contain the femoral head within the acetabulum during healing to prevent deformity.